Most studies involving 'competitive helping' involve games played in a lab so scholars are delighted to have real-world data. Nichola Raihani of University College London and Sarah Smith of the University of Bristol used a UK-based, online fundraising platform to test whether males respond competitively to the generosity bids of other males in the presence of attractive females. On the platform, people host fundraising pages including their personal information--name, photo, charity, and the event they are being sponsored for--and collect donations.
Donations are made and posted sequentially, along with the name of the donor, unless they've opted for anonymity. Smith's earlier work found that existing donations on a page act as a kind of "anchor" for current donors. In other words, seeing a small or a large donation influenced what subsequent donors were willing to contribute. Raihani and Smith wanted to know whether the behavior of donors would also be influenced by the gender and attractiveness of the fundraiser, along with the gender of the previous donor.
So much for altruism, right? No, not even evolutionary psychology would claim attractiveness is all people care about. It may be that males are inclined to give something anyway and seeing an attractive woman and a competitor just 'ups the ante'.
"I think it is more likely that humans have an evolved psychology that motivates us to behave in ways that would have been, on average, adaptive in our evolutionary past--and may still be nowadays also," says Raihani.
So if you want to have a successful fundraising campaign:
1) Use an attractive woman.
2) Have her smile.
3) Have a male who was going to donate anyway make the donation early so that other males obey their biological mandate.
Citation: Raihani, N. and Smith, S., "Competitive Helping in Online Giving", Current Biology hDOI:10.1016/j.cub.2015.02.042